Containment system for particulate materials

ABSTRACT

A containment system for particulate materials comprises a substantially vertical annular wall defining a substantially cylindrical storage area. A plurality of membrane supports are each attached near an outer end thereof to an upper edge of the wall and extend inwardly and upwardly to a central location above a central portion of the storage area where inner ends of each membrane support are secured to each other. An impermeable flexible membrane is attached at an outer edge thereof to the wall and extends over the membrane supports to enclose the storage area. Curved membrane supports are provided that reduce flapping of the membrane in the wind, and the supports may also be provided with a lower tensioner, thereby increasing strength.

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/427,562 entitled “Containment System For Particulate Materials”, filed Oct. 26, 1999. This invention relates to bins for storing granular or particulate material such as grain and in particular provides an improved system for the storage of such material.

BACKGROUND

[0002] As production costs continue to climb and crop yields vary greatly from year to year, agricultural producers find themselves on occasion faced with the situation of not having enough storage space for all of their crop yield. Conventionally, grain bins of either a flat-bottomed or hopper-bottomed variety, or even quonsets or other buildings, were used to store grain and if more storage was required more bins or buildings would be erected.

[0003] The most popular type of grain bins available are flat-bottomed bins erected from panels of corrugated steel. However, by the time the bin is erected and a roof placed thereon, the cost per bushel of erecting this storage is substantial. The erection of such storage bins also takes some degree of time as several rings or layers of steel panels are generally speaking bolted together to form a bin of any substantial height or capacity.

[0004] Another problem with metal grain bins is that as the size is increased, substantial strengthening is involved by way of significantly increased steel gauge or other supports to hold up the large and heavy walls of such a storage bin.

[0005] Many alternatives have been seen for the storage of grain or other particulate material. For example, the most basic of these might be to simply pile the extra grain or material on a flat area of ground. It is difficult to protect such piled material from the elements.

[0006] Farmers have also been known to form rings of bales, plywood and the like and pile grain inside the ring such that the grain rises to the top of the ring and forms a peak substantially above the top of the ring. The ring restricts the outward flow of grain so that less ground is covered. As well a tarp or like flexible membrane can be pulled over the peaked grain and secured to the ring to protect the grain from the elements. Recently such rings have become commercially available which are formed from metal and include a formed membrane top that fits the ring and the peaked grain. Such commercial rings and membrane tops are popular because they are significantly cheaper than a conventional grain bin of comparable capacity.

[0007] A significant problem with such rings is that the membrane top is supported only by the grain. The ring must be filled before the membrane can be installed, and the membrane must then be pulled over the peak of grain which can be difficult, especially where the rings are large. Also, when only a portion of the grain stored in such a ring is removed, the membrane becomes unsupported and sags beneath the top of the ring such that rain and snow run down inside the ring rather than outside, causing damage to the remaining grain. In such a partially empty ring, it is also very difficult to secure the membrane against movement by the wind.

SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to provide a containment system for grain or other particulate materials that includes a flexible membrane top supported by the system rather than by the contents of the system.

[0009] It is a further object of the present invention to provide such a containment system that includes curved membrane supports to support the membrane such movement of the membrane in the wind is reduced.

[0010] It is a further object of the present invention to provide such a containment system wherein the curved membrane supports are easily constructed using a tensioner, the tensioner also increasing the strength of the membrane supports.

[0011] The invention, a containment system for particulate materials, comprises a substantially vertical annular wall defining a substantially cylindrical storage area. A plurality of membrane supports are each attached near an outer end thereof to an upper edge of the wall and extend inwardly and upwardly to a central location above a central portion of the storage area where inner ends of each membrane support are secured to each other. An impermeable flexible membrane is attached at an outer edge thereof to the wall and extends over the membrane supports to enclose the storage area.

[0012] The membrane supports are displaced within the storage area, such that each membrane support engages the flexible membrane to support same. The membrane supports are attached to the wall and extend upwards and inwards therefrom, and can be self supporting. The membrane may be installed on top of the membrane supports, and will be maintained in position whether the bin is full or empty, or partially empty. Vertical supports may be added to support a mid-point of the membrane supports where spans are large.

[0013] Preferably the membrane supports are curved such that a concave side thereof faces generally downward. With such curved membrane supports, when tension is applied to tighten the membrane onto the wall, the membrane is pulled down against the top of the membrane supports and flapping caused by wind is reduced. The curved membrane support is easily formed from a substantially straight elongated member with a tensioner attached to each end and drawn tight to force the straight member into the desired curved position. The resulting curved member with attached tensioner has the benefit of being stronger than the straight member, with little added weight. Longer spans may thus be accomplished.

DESCRIPTION OF THE DRAWINGS

[0014] While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where:

[0015]FIG. 1 is a side view of one embodiment of the system of the present invention where the membrane supports are straight, with the membrane removed;

[0016]FIG. 2 is a top view of the embodiment of FIG. 1, also with the membrane removed;

[0017]FIG. 3 is a side view of the embodiment of FIG. 1, with the membrane in place;

[0018]FIG. 4 is a side view of an alternate embodiment of the system of the present invention where the membrane supports are curved, with the membrane removed;

[0019]FIG. 5 is a top view of the embodiment of FIG. 4, also with the membrane removed;

[0020]FIGS. 6 and 7 show how the curved membrane supports may be formed;

[0021]FIG. 8 is a side view of the embodiment of FIG. 4, with the membrane in place;

[0022]FIG. 9 is a top view of the embodiment of FIG. 4, with the membrane in place;

[0023]FIG. 10 is an end view showing the shape of a typical curved membrane support.

[0024]FIG. 11 is a schematic side view of a tensioning rod passing through the wall allowing tensioning of the curved membrane supports, and thus the membrane, form outside the structure;

[0025]FIG. 12 is a side view of an embodiment wherein the wall has pronounced recesses, allowing the membrane to be tightened using a circumferential force;

[0026]FIG. 13 is a schematic of the action of the membrane in the embodiment of FIG. 12.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0027] FIGS. 1-3 show one embodiment of the containment system of the present invention. The containment system 1 comprises a substantially vertical annular wall 2 defining a substantially cylindrical storage area 3. The wall 2 has am upper edge 4. The annular wall 2 is illustrated as circular but could also be elliptical.

[0028] Each of a plurality of membrane supports 5 is attached near an outer end 5A thereof to the upper edge 4 of the wall 2, and extends inwardly and upwardly to a central location 7 above a central portion of the storage area 3 where inner ends 5B of each membrane support 5 are secured to each other. In the embodiment illustrated, the inner end 5B of each membrane support 5 is attached to a hatch member 8. The hatch member 8 defines a hatch opening 9.

[0029] As shown in FIG. 3, an impermeable flexible membrane 10 is attached at an outer edge 11 thereof to the wall 2 and extends over the membrane supports 5 to enclose the storage area 3. The outer edge 11 is attached to the outside of the wall 2 by a rope 6 passing through holes in the outer edge 11 of the membrane 10 and hooked onto hooks 16 on the outside of the wall 2. The outer edge of the membrane is thus attached to the outside of the wall. The rope 6 provides a means to exert a downward force on the outer edge 11 of the membrane 10. The rope 6 could alternatively be fastened to the ground, and rather than the rope 6, tension could be supplied by turnbuckles, winches, or the like attached at intervals around the outer edge 11 of the membrane 10.

[0030] The outer edge 11 is somewhat below the upper edge 4 of the wall 2 so that rain and snow will slide down the slope of the membrane 10 and outside the storage area 3. In the illustrated embodiment the membrane 10 also defines an aperture 12 coincidental with the hatch opening 9, such that particulate material such as grain or the like may be deposited into the storage area 3 through the hatch opening 9.

[0031] Thus the membrane supports 5 support the membrane 10, rather than as in conventional grain rings where the grain must support the membrane 10. The membrane supports 5 allow the storage area 3 to be filled and emptied, or partially emptied, with the membrane 10 secured in place against sagging and movement by wind.

[0032] While the membrane supports 5 will support the membrane 10 with no internal supports, the size of the membrane support 5 required to supply the necessary strength can be excessive where large diameter storage areas 3 are needed. Rather than increase membrane support size and strength, a plurality of substantially vertical members 15 can be located between the wall 2 and the central location 7 having a lower end resting on the bottom of the storage area and a top end supporting a mid-point of the membrane supports 5. In the embodiment illustrated, a substantially horizontal annular member 17 is supported by the vertical members 15, and in turn supports a mid-point of the membrane supports 5.

[0033] The wall 2 comprises a plurality of wall sections 2A joined to each other at ends thereof to form the wall 2. The wall 2 also defines an access door 18 for access and unloading material from the storage area.

[0034] In an alternate embodiment illustrated in FIGS. 4, 5, 8, and 9, the membrane supports 5C are curved from the inner end 5B to the outer end 5A thereof, and are oriented such that the concave side 25 of the membrane support 5C is facing generally downward. The curved membrane support is a considerable aid in maintaining the membrane 10 tight. Where the membrane supports 5 are substantially straight from the inner end 5B to the outer end 5A, as in the embodiment of FIGS. 1-3, the membrane 10 lies flat against the top of the membrane supports 5, and even with considerable tension on the rope 6, the membrane will flap in the wind, causing wear and stress on the membrane 10 and rope 6. However where the membrane supports 5C are curved as illustrated, the membrane 10 follows the curve such that tension on the rope 6 provides a force component on the membrane exerted towards the top of the membrane support 5C. Flapping of the membrane 10, and thus the associated wear and stress, is thereby much reduced.

[0035] The curved membrane support 5C is conveniently formed as illustrated in FIGS. 6 and 7. A tensioner 30, such as a cable 31 and winch 32 or turnbuckle 33, is attached at an inner end 30B thereof near the inner end 5B of a substantially straight membrane support member 5S, and attached at an outer end 30A thereof near an outer end 5A of the membrane support member 5S. The tensioner 30 is tightened by drawing up the winch 25 or turnbuckle 33 to force the membrane support 5S into the curved position 5C.

[0036] A spacer 29 can be mounted between the membrane support 5C and the tensioner 30 near the mid-point of the tensioner 30 and arranged to maintain a constant distance between the membrane support 5C and the tensioner 30. The spacer 29 adds stability to the system.

[0037] The tensioner 30 could be tightened after the membrane 10 was put in place, thus allowing the membrane to be attached to the wall 2 and tightened after by increasing the curvature of the membrane supports 5C. The rope 6 might not then be required as the outer edge 11 of the membrane 10 could be fixed to the wall 2.

[0038] An end view showing a typical shape of such a membrane support 5C is illustrated in FIG. 10. The flattened oval tube 35 is well suited to the function.

[0039]FIG. 11 illustrates one way that the membrane support 5C could be tensioned from outside the wall 2. Tensioning rod 34 could extend through a hole 36 in the wall 2. A nut 37 is threaded on the rod 34 and is used to adjust the tension on the membrane support 5C.

[0040] The amount of draw required on the tensioner 30 is not great. A draw of two inches on a 28 foot member will curve the membrane support 5C such that there is about a foot between the membrane support 5C and the tensioner 30. This curvature is enough to reduce flapping of the membrane 10 considerably.

[0041] The tensioner 30 of the curved membrane support 5C extends across the concave side of the membrane support 5C and exerts a tension holding the membrane support 5C in the curved position. The curved membrane support 5C thus forms a truss-like structure with increased strength. A force F exerted on the concave side of the membrane support 5C causes in turn forces F′ at the ends 5A, 5B of the membrane support 5C, which are counteracted by increased tension on the tensioner 30, thereby resisting bending.

[0042]FIG. 12 illustrates a further embodiment of the invention wherein the wall 2 has a pronounced recess 40. The membrane 10 is sized such that the outer edge 11 thereof will fit easily onto the top of the slope 42 of the recess 40 in the wall 2. A cord 41 is runs around the outer edge 11 of the membrane 10 in a pocket 43. The cord 41 is exposed at ratchet 44 such that ratchet 44 can draw the cord 41 tight.

[0043] As illustrated in FIG. 13, the circumferential force CF exerted by the ratchet 44 has a component of force in direction R such that the outer edge of the membrane is drawn down the slope 42, thereby applying downward force on the membrane 10 and tightening same to the membrane supports 5C. The circumferential cord 41 has the further benefit of drawing the outer edge 11 of the membrane 10 tight against the wall 2 so, preventing wind from entering under the membrane 10.

[0044] The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention. 

We claim:
 1. A containment system for particulate materials, said system comprising: a substantially vertical annular wall defining a substantially cylindrical storage area, the wall having an upper edge; a plurality of membrane supports, each attached near an outer end thereof to the upper edge of the wall and extending inwardly and upwardly to a central location above a central portion of the storage area where inner ends of each membrane support are secured to each other; and an impermeable flexible membrane attached at an outer edge thereof to the wall and extending over the membrane supports to enclose the storage area.
 2. The containment system of claim 1 further comprising a plurality of substantially vertical members located between the wall and the central location and having a lower end resting on a bottom of the storage area and a top end supporting a mid-point of the membrane supports.
 3. The containment system of claim 2 further comprising a substantially horizontal annular member supported by the vertical members and supporting a mid-point of the membrane supports.
 4. The containment system of claim 1 further comprising a hatch member, and wherein the inner end of each membrane support is attached to the hatch member.
 5. The containment system of claim 4 wherein the hatch member defines a hatch opening and wherein the membrane defines an aperture coincidental with the hatch opening.
 6. The containment system of claim 1 wherein the outer edge of the membrane is attached to at least one of an outside of the wall or the ground.
 7. The containment system of claim 6 further comprising means to exert a downward force on the outer edge of the membrane.
 8. The containment system of claim 7 wherein the downward force is exerted by a cord around the outside edge of the membrane, the cord exerting a circumferential force such that the outer edge of the membrane moves down a slope defined by the wall.
 9. The containment system of claim 1 wherein the membrane supports are curved from the inner end to the outer end, and wherein a concave side of the membrane support is facing generally downward.
 10. The containment system of claim 9 wherein the outer edge of the membrane is attached to at least one of an outside of the wall or the ground.
 11. The containment system of claim 10 further comprising means to exert a downward force on the outer edge of the membrane.
 12. The containment system of claim 11 wherein the downward force is exerted by a cord around the outside edge of the membrane, the cord exerting a circumferential force such that the outer edge of the membrane moves down a slope defined by the wall.
 13. The containment system of claim 9 further comprising a tensioner attached at an inner end thereof near the inner end of a membrane support, and attached at an outer end thereof near an outer end of the membrane support, the tensioner extending across the concave side of the membrane support and exerting a tension holding the membrane support in a curved position.
 14. The containment system of claim 13 further comprising a spacer mounted between the membrane support and the tensioner in proximity to a mid-point of the tensioner and arranged to maintain a constant distance between the membrane support and the tensioner.
 15. The containment system of claim 13 wherein the tensioner is attached to the membrane support when the membrane support is substantially straight, and wherein the tensioner is tightened to force the membrane support into the curved position.
 16. The containment system of claim 15 wherein the tensioner can be tightened after the membrane is installed.
 17. The containment system of claim 16 wherein the tensioner can be tightened from outside the wall.
 18. The containment system of claim 15 wherein the tensioner further comprises a turnbuckle.
 19. The containment system of claim 15 wherein the tensioner further comprises a winch.
 20. The containment system of claim 15 wherein the tensioner comprises a threaded rod. 